How to change my profile name

You can contact the hosts by email here —> communityaccounts@apple.com

Contacting them by email with a few name suggestions means they may be able to give you one of those. Otherwise the hosts appear to randomly assign you one—which you may or may not like. If you find you have one assigned by the hosts without consultation then it may be another community helper reported your wish directly to the hosts. If you want a name you would like I would act quickly. ;-)

Getting a new community name is a bit of an exception so choose one that you like permanently.